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Research paper−150−Synthesiology - English edition Vol.5 No.3 pp.150-159 (Dec. 2012) only one die (= mandrel) is necessary, or in some cases a mandrel is unnecessary, meaning that the cost of tooling can be kept low compared with that of the pressed products and the production process can be set up quickly. Currently, the processing time necessary per product is several tens of seconds to several minutes, making it unsuitable for mass production. However, it is expected to be very useful in high-mix low-volume production, one-time special orders, and prototype fabrication.To form noncircular shapes, two methods, force-controlled spinning and synchronized spinning, are used. These enable the forming of noncircular shapes that cannot be made by a conventional spinning machine for circular products or by manual metal spinning by a skilled worker. In force-controlled spinning, a mandrel of the same shape as the desired noncircular shape is used to form the product.[3] By controlling the pushing force of the roller at an appropriate 1 Outline of the developed technologyMetal spinning is a plastic forming method in which a metal blank such as a sheet or pipe is rotated by a motor and formed into a desired shape by pressing a roller tool against the material (Fig. 1).[1] This method can be applied to various metal materials, including aluminum, iron, and stainless steel, as a method of creating hollow metal products. It is used widely in various industries including lighting equipment, cooking utensils, automobiles, electrical appliances, chemical plants, pressure vessels, aerospace parts, and architectural decorations. Manual metal spinning is called hera shibori in Japanese, and it is known as one of the most advanced craftsman’s skills in manufacturing. The advantages of spinning are as follows: 1) the tooling cost is low since only a male die is necessary, 2) the yield rate of the material is better than that of a cutting process, and 3) the equipment is small and does not make much noise or vibration because the force required in processing is small.The author has been attempting to introduce robot control technology to metal spinning to enable processing with high additional value.[2]-[6] In particular, we have developed spinning machines and methods that enable the forming of noncircular shapes such as elliptical, polygonal, and eccentric shapes. Other than circular objects, which can be formed by regular metal spinning, conventionally hollow metal products have to be manufactured by sheet bending and welding, which is a complicated procedure, or drawing, which requires expensive dies. In the new process, in general, - Field-based bricolage of manufacturing technology-Metal spinning is a plastic forming method in which a rotating metal material is pushed by a roller to form a product. It is suitable for the production of a wide variety of products in small quantities owing to the low cost of forming dies. We have achieved the fabrication of noncircular shapes by using robot technology, which is difficult to realize by conventional methods. A prototype of a practical spinning machine has been developed in collaboration with a spinning machinery manufacturer. In this research, we have basically set our preference for commercial realization over academic contribution. This research was carried out in a bottom-up and trial-and-error manner, and the targets of this research were frequently modified depending on the situation. Bricolage, utilizing the combination of available and limited resources at hand, played a key role in the research activity. Decision-making reflected three-actuals theory, which values the actual field site, actual object, and actual situation. We included increased customer satisfaction in the criteria of value and carried out sales activities as a part of the research.Spinning process using robot technologyKeywords : Metal spinning, robot, metal forming, bottom-up, bricolage, san-gen-shugi[Translation from Synthesiology, Vol.5, No.2, p.126-134 (2012)]Hirohiko AraiAdvanced Manufacturing Research Institute, AIST 1-2-1 Namiki, Tsukuba 305-8564, Japan E-mail: Original manuscript received January 26, 2012, Revisions received March 5, 2012, Accepted March 7, 2012Fig. 1 Metal spinning (sheet)MaterialMandrela) Conventional (multipass) spinningMaterialMandrelRollerb) Shear spinningRoller

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